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People question whether dogs eating cat food is OK – for the dog! The cat will be a bit miffed having had her food stolen but this article discusses the ins and outs of dogs eating food for cats.

Dogs eat pretty much anything including cat feces and/or cat litter – gruesome. The answer as to whether it is bad for the dog’s health in the long term must come from a discussion about the nutritional requirements of dogs and cats. Pet food manufacturers try, within commercial considerations, to provide food that is carefully matched to the requirements of the animal.

We know that cats are “obligate carnivores”. They eat meat (the flesh of other animals) to live. In the wild it is almost exclusively the flesh of prey. I say nearly exclusively because prey does contain some vegetable matter in the stomach and as it happens some wildcats – I am thinking of the snow leopard – do eat a fair bit of pure vegetation. The situation is never black and white.

However, it means that cat food should be high in protein and fat content. The mouse, the classic prey of the domestic cat, is 50% fat, 40% protein and just 3% carbohydrate.

Incidentally, sometimes cat food is not that suited to cats, which begs the question whether cheap cat food, which is not high in protein but full of carbohydrates and grain etc. is equally suitable for a dog.

Is the dog a carnivore or omnivore? There appears to be a discussion about that. The answer is crucial. It dictates whether the dog is the fundamentally the same as the cat in its nutritional requirements. Probably the best answer comes from the website Dog Food Advisor. The author says that the dog is an omnivore with a carnivorous bias. The dog is a domesticated timber wolf. The wolf is a carnivore. However, over the 15,000 years of domestication the dog has developed omnivorous habits it seems.

The upshot is that cats apparently require two to three times more protein in their diet than dogs1. Or put it another way, in recognition of the omnivorous qualities of the modern domestic dog, it requires half to one third the protein requirements of the modern domestic cat.

If dog food should never be fed to a cat it is fair to argue that cat food should not be fed to a dog despite the dog’s greater flexibility in respect of dietary requirements.

In conclusion, cat food contains too much protein for the dog. How does this affect the dog? Well, the consensus would seem to be that a dog might prefer the richer (in fat) cat food but it may lead to obesity, which in turn affects health. The dog might get diarrhea or other digestive problems . These are not necessarily serious and it would probably take long term eating of cat food to develop problems. In the short term it would appear to be OK.

However, there are no advantage to dogs eating cat food as the price is similar and you buy cat and dog food from the same place so it is not inconvenient to buy both.